Storage silos for the storage of grain, feed and the like can be either of the top unloader type, or bottom unloader type. It is often preferred to utilize silos of the bottom unloader type, in that, by withdrawing silage from the bottom of the silo, the oldest silage is utilized first, as well as for many other reasons. The present invention is directed toward bottom unloaders for silos.
Bottom unloaders have also been developed in the past, but difficulties with such unloaders have very often been experienced, in that the tremendous weight of silage upon the bottom unloaders often compact silage about the unloaders, acting as a brake, and jamming the operation of the unloader.
Particularly, when the unloader is of the auger type, with teeth of other suitable cutting devices for cutting silage as an auger is rotated about its axis, and for propelling or otherwise conveying silage thus cut, to a generally central location, it is also necessary to move such an auger across the floor of a silo.
If such an auger is of a radial type, adapted for a sweeping motion about a center, for example, of a generally cylindrical silo, such may sweep across the floor of the silo, cutting a path, with silage from an upper part of the silo then falling downwardly into the zone previously traversed by the auger.
It has been found that such augers must be constructed in such a manner as to withstand tremendous silage forces.
Also, there is present the problem of how to drive the auger in its sweeping motion. Some systems have been developed, whereby a motor or the like may be mounted at a radial outermost end of an auger for driving a member which in turn, is engagable with another member at the periphery of the silo floor, or inside the silo wall. However, if a motor of the like is adapted for movement with the auger about the silo, in its sweeping action, should the auger become jammed, it may be exceedingly difficult, if not impossible to service the motor.
Additionally, in prior art types of devices, and even in the devices of my own prior applications set forth above, in order to remove the silage that is disposed up close against the silo wall, the use of auxiliary augers has been required. This is because, in making its initial sweep across the floor of a silo, it has been found that it is first desirable to make an initial dome-like structure, by the use of an auger that has a radial outermost end that is spaced considerably from the silo wall. Also, by making an initial sweep that is somewhat shortened or spaced from the silo wall, as measured radially, less resistance to the advance of the auger is encountered. On subsequent passes, auxiliary augers have been placed on the outer ends of the augers, a practice which requires a certain amount of time and inconvenience, in necessitating the replacement of different sized augers, or even just in the placement of a single auxiliary auger at the end of the auger. Also, other types of cutters have been utilized, but such also require discontinuance of the use of the auger so that the changes may be made in the outer end of the auger in order that the auger may then approach more closely the silo wall, in a subsequent sweep or advancing motion.
Prior art types of devices have also not in all instances provided adequate facilities for discharge of silage, after the silage is delivered to a generally centrally disposed bottom opening thereof.